An extract of Curcuma longa (CL) was effective at reducing pain, but not structural features of disease among patients with osteoarthritis. These findings, from a randomized, double-blind, placebo-controlled trial, were published in the Annals of Internal Medicine.
Patients (N=70) with symptomatic knee osteoarthritis and effusion-synovitis were recruited between 2018 and 2019 at the Menzies Institute for Medical Research in Australia. Participants were randomly assigned in a 1:1 ratio to receive either 1000 mg/d CL (n=36) or placebo (n=34) daily for 12 weeks. Patients were assessed for knee pain by a visual analogue scale (VAS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), for change of knee effusion-synovitis by magnetic resonance imaging (MRI), and for response to treatment by the Outcome Measures in Rheumatology Clinical Trials (OARSI-OMERACT).
At baseline, differences in WOMAC scores were not clinically significant between the group receiving CL and those receiving placebo.
After 12 weeks, participants in the treatment and placebo groups differed significantly for VAS knee pain score (-23.8 mm vs -14.6 mm; P =.039), WOMAC pain score (-84.2 mm vs -37.0 mm; P =.006), function score (-292.0 mm vs -179.7 mm; P =.047), stiffness score (-41.1 mm vs -20.9 mm; P =.019), weight-bearing pain (-54.7 mm vs -28.8 mm; P =.018), non-weight-bearing pain (-29.6 mm vs -8.3 mm; P =.005), and OARSI-OMERACT (22% vs 13%; P =.035), respectively.
Patients in the treatment group also reported greater improvement of their WOMAC pain (P =.006), function (P =.047), weight-bearing pain (P =.018), and non-weight-bearing pain (P =.005) scores compared with those in the placebo group. At 12 weeks, 62.9% of the treatment group and 38.2% of the placebo group were OARSI-OMERACT responders (P =.035).
No significant difference for effusion-synovitis volume was detected by MRI between the treatment group (1.1 mL; 95% CI, -1.3 to 3.2 mL) and placebo group (-2.1 mL; 95% CI, -4.6 to 0.4 mL).
More patients in the placebo group (58%) than in the treatment group (39%) reported adverse events during the study. A patient in the CL group withdrew from the study at 8 weeks because of an uncomfortable feeling at the top of their stomach. Only 87% of participants consumed more than 80% of their capsules at study conclusion.
The limitations of this study included the sample size and the duration. This study aimed to assess the effect of CL on synovitis, however, 12 weeks was likely insufficient for assessing alterations to connective and cartilage tissues.
The study authors concluded that patients who were treated with CL had decreased pain from their knee osteoarthritis and effusion-synovitis. However, this effect was moderate, and no evidence of structural alterations were observed.
Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.
Wang Z, Jones G, Winzenberg T, et al. Effectiveness of Curcuma longa extract for the treatment of symptoms and effusion–synovitis of knee osteoarthritis: a randomized trial. Published online September 15, 2020. Ann Intern Med. doi:10.7326/M20-0990